U.S. patent number 5,196,025 [Application Number 07/526,290] was granted by the patent office on 1993-03-23 for lancet actuator with retractable mechanism.
This patent grant is currently assigned to Boehringer Mannheim Corporation, Ryder International Corporation. Invention is credited to Joseph V. Ranalletta, Fred E. Williams, Jr..
United States Patent |
5,196,025 |
Ranalletta , et al. |
March 23, 1993 |
Lancet actuator with retractable mechanism
Abstract
The present invention provides an actuator mechanism for
sequentially advancing and retracting a lancet needle and includes
a drive carriage for advancing and retracting the lancet needle and
a hinge structure operatively connected to displace the drive
carriage. The hinge structure includes first and second coupled
leaf members relatively pivotal between a first position thereof in
which the drive carriage is advanced to project and thrust the
lancet needle into a tissue penetration position, and the second
pivotal position of the leaf members in which the drive carriage is
retracted to withdraw the lancet needle from the penetration
position. The leaf members can also be pivotal to a third position
in which the drive carriage is retracted prior to initiating the
advancement so that the first position of the leaf members is
pivotally intermediate between the second and third relative
positions thereof. The drive carriage is thus advanced and
thereafter retracted for thrusting and then withdrawing the lancet
needle in continuous reversal motions thereof. The drive carriage
is guided so that the advancement and retraction motions are along
a highly accurate linear path.
Inventors: |
Ranalletta; Joseph V.
(Guntersville, AL), Williams, Jr.; Fred E. (Arab, AL) |
Assignee: |
Ryder International Corporation
(Arab, AL)
Boehringer Mannheim Corporation (Indianapolis, IN)
|
Family
ID: |
24096727 |
Appl.
No.: |
07/526,290 |
Filed: |
May 21, 1990 |
Current U.S.
Class: |
606/182; 600/583;
606/185 |
Current CPC
Class: |
A61B
5/15186 (20130101); A61B 5/150022 (20130101); A61B
5/150412 (20130101); A61B 5/15113 (20130101); A61B
5/15117 (20130101); A61B 5/15144 (20130101); A61B
5/15194 (20130101); A61B 5/150259 (20130101) |
Current International
Class: |
A61B
5/15 (20060101); A61B 005/00 () |
Field of
Search: |
;606/181,182 ;128/770
;604/136,192-198 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Yasko; John D.
Assistant Examiner: Lewis; William W.
Attorney, Agent or Firm: Trexler, Bushnell, Giangiorgi &
Blackstone, Ltd.
Claims
We claim:
1. A mechanism for sequentially advancing and retracting a lancet
needle, comprising:
(a) drive carriage means for carrying, advancing, and retracting
the lancet needle;
(b) a hinge structure operatively connected to linearly displace
said drive carriage means on a linear path along an axis of said
drive carriage means and including first and second coupled leaf
members, said drive carriage means being connected to one of said
first and second leaf members which are relatively pivotal between
a first position thereof in which said drive carriage means is
advanced to project and thrust the lancet needle into a tissue
penetration position and a second position in which said drive
carriage means is retracted from said advance to withdraw the
lancet needle from the penetration position the other of said first
and second leaf members being further coupled to a pivot bearing
structure of said mechanism for supporting said relative pivot.
2. A mechanism according to claim 1, wherein said leaf members are
relatively pivotal to a third position thereof in which said drive
carriage means is retracted prior to initiating said advancement to
said first position.
3. A mechanism according to claim 2, wherein said first position of
said leaf members is pivotally intermediate between said second and
third relative positions thereof.
4. A mechanism according to claim 1, further comprising control
means for actuating relative pivotal movement of said leaf members
from said third position through said first position into said
second position such that said drive carriage means is advanced and
thereafter retracted for thrusting and then withdrawing said lancet
needle in continuous motions thereof.
5. A mechanism according to claim 4, wherein said. control means
comprises energy storage means for propelling said relative pivotal
motion of said first and second leaf members.
6. A mechanism according to claim 5, wherein said energy storage
means comprises spring means bearing against said first leaf member
and propelling pivotal movement thereof relative to said second
leaf member.
7. A mechanism according to claim 1, further comprising guide means
for guiding said advancement and retraction of said drive carriage
means along a linear displacement path.
8. A mechanism according to claim 1, wherein said first and second
leaf members are pivotally extended at an angle of 180.
therebetween in said first position.
9. A mechanism according to claim 1, wherein said hinge structure
includes a first pivot bearing means pivotally coupling said first
and second leaf members, said first pivot bearing means being
pivotal about a second pivot bearing means during said relative
pivot of said first and second leaf members.
10. A mechanism according to claim 1, wherein said hinge structure
further comprises a second, translationally stationary pivot
bearing means secured to one end of said first leaf member and an
opposite end of said first leaf member is secured to a first pivot
bearing means pivotally coupling said first and second leaf
members, said first pivot bearing means being pivotal about said
second pivot bearing means during said relative pivot of said first
and second leaf members between said first and second
positions.
11. A mechanism according to claim 10, further comprising control
means for actuating said pivot of said leaf members.
12. A mechanism according to claim 11, wherein said control means
comprises spring means bearing against said first leaf member and
propelling pivot thereof relative to said second leaf member.
13. A mechanism according to claim 12, wherein said control means
further comprises retention means for releasably retaining energy
of said spring means for said propulsion.
14. A mechanism according to claim 13, wherein said retention means
comprises manually operable release means for releasing said spring
means energy.
15. A mechanism according to claim 1, further comprising spring
means bearing against said first leaf member for propelling pivot
thereof relative to said second leaf member, and cocking means for
energizing said spring means.
16. An actuating mechanism for sequentially advancing and
retracting a lancet needle, comprising:
a) drive carriage means for carrying, advancing, and retracting the
lancet needle;
b) a hinge structure operatively connected to displace said drive
carriage means and including first and second coupled leaf members,
said drive carriage means being connected to said second leaf
member, said first and second leaf members being relatively pivotal
between a first position thereof in which said drive carriage means
is advanced to project and thrust the lancet needle into a tissue
penetration position and a second position in which said drive
carriage means is retracted from said advance to withdraw the
lancet needle from the penetration position, wherein said hinge
structure further comprises a second, translationally stationary
pivot bearing means secured to one end of said first leaf member
and an opposite end of said first leaf member is secured to a first
pivot bearing means pivotally coupling said first and second leaf
members, said first pivot bearing means being pivotal about said
second pivot bearing means during said first and second positions
and wherein said second pivot bearing means comprises a rotational
hub member on which a torsion spring bears for propelling pivot of
said first leaf member.
17. A mechanism according to claim 16, comprising control means for
actuating rotation of said hub member and pivot of said first leaf
member.
18. A mechanism according to claim 17, wherein said control means
comprises manually operable trigger means for releasing tension in
said torsion spring for said propulsion.
19. A mechanism according to claim 18, wherein said trigger means
comprises a cam portion projecting from said hub member and
releasably engaged by a deflectable trigger latch member for
retaining said tension torsion spring until manual deflection of
said trigger latch releases the engagement of said can and said
tension.
20. An actuating mechanism for sequentially advancing and
retracting a lancet needle, comprising:
a) drive carriage means for carrying, advancing, and retracting the
lancet needle;
b) a hinge structure operatively connected to displace said drive
carriage means and including first and second coupled leaf members,
said drive carriage means being connected to said second leaf
member, said first and second leaf members being relatively pivotal
between a first position thereof in which said drive carriage means
is advanced to project and thrust the lancet needle into a tissue
penetration position and a second position in which said drive
carriage means is retracted from said advance to withdraw the
lancet needle from the penetration position, further comprising
spring means bearing against said first leaf member for propelling
pivot thereof relative to said second leaf member, and cocking
means for energizing said spring means, wherein said cocking means
is movably biased toward a neutral position thereof removed from
energizing said spring means.
21. An actuating mechanism for sequentially advancing and
retracting a lancet needle, comprising:
a) drive carriage means for carrying, advancing, and retracting the
lancet needle;
b) a hinge structure operatively connected to displace said drive
carriage means and including first and second coupled leaf members,
said drive carriage means being connected to said second leaf
member, said first and second leaf members being relatively pivotal
between a first position thereof in which said drive carriage means
is advanced to project and thrust the lancet needle into a tissue
penetration position and a second position in which said drive
carriage means is retracted from said advance to withdraw the
lancet needle from the penetration position, wherein said hinge
structure further comprises a pivot bearing rotational hub secured
to one end of said first leaf member on which a spring means bears
for propelling said pivot of said first leaf member, and further
comprising a cocking member selectively engageable with either said
hub for energizing said spring means, or engageable with said drive
carriage means for detatchment of a lancet structure removably
carried on said drive carriage means.
22. An actuating mechanism for sequentially advancing and
retracting a lancet needle, comprising:
a) drive carriage means for carrying, advancing, and retracting the
lancet needle;
b) a hinge structure operatively connected to displace said drive
carriage means and including first and second coupled leaf members,
said drive carriage means being connected to one of said first and
second leaf members which are relatively pivotal between a first
position thereof in which said drive carriage means is advanced to
project and thrust the lancet needle into a tissue penetration
position and a second position in which said drive carriage means
is retracted from said advance to withdraw the lancet needle from
the penetration position, the other of said first and second leaf
members being further coupled to a pivot bearing structure of said
mechanism, wherein said drive carriage means comprises a housing
structure for removably receiving a body portion of a lancet
structure, said body portion being slidably received and withdrawn
through an access aperture formed in said housing structure.
23. A mechanism according to claim 22, wherein said drive carriage
housing structure includes a through slot through which an ejection
portion of said cocking member enters said housing structure and
displaces said lancet structure therefrom through said access
aperture in order to achieve said detachment of said lancet
structure therefrom.
24. A mechanism according to claim 22, further comprising a housing
for containing and supporting said mechanism, said housing having a
stop member secured therein for engagement with said drive carriage
housing structure at a terminally retracted position thereof in
order to hold said drive carriage housing structure stationary
during slidable insertion of said lancet body and structure
therein.
25. A mechanism for sequentially advancing and retracting a lancet
needle, comprising:
a) drive carriage means for carrying, advancing, and retracting the
lancet needle;
b) a hinge structure operatively connected to displace said drive
carriage means and including first and second coupled leaf members
which are relatively pivotal between a first position thereof in
which said drive carriage means is advanced to project and thrust
the lancet needle into a tissue penetration position and a second
position in which said drive carriage means is retracted from said
advance to withdraw the lancet needle from the penetration
position, wherein said drive carriage means and said first and
second leaf members are integrally molded and defined within a
unitary molded structure wherein said drive carriage means is
connected to said second leaf member by a first attenuated portion
of said molded structure forming a flexible hinge coupling between
said second leaf member and said drive carriage means, and wherein
said first and second leaf members are joined by a second
attenuated portion of said unitary molded structure pivotally
coupling said leaf members, said first leaf member being further
coupled to a pivot bearing structure therefor, such that said
relative pivot of said first and second leaf members produces said
advancement and retraction of said integrally connected drive
carriage means.
26. An actuating mechanism for sequentially advancing and
retracting a lancet needle comprising:
a) drive carriage means for carrying, advancing, and retracting the
lancet needle;
b) a hinge structure operatively connected to displace said drive
carriage means and including first and second coupled leaf members
relatively pivotal between a first position thereof in which said
drive carriage means is advanced to project and thrust the lancet
needle into tissue penetration position and a second position in
which said drive carriage means is retracted to withdraw the lancet
needle from the penetration position thereof, wherein said drive
carriage means and said first and second leaf members are
integrally molded and in which said drive carriage means is
connected to one of said first and second leaf members by a first
flexible hinge coupling portion, the other of said first and second
leaf members being further coupled to a pivot bearing support
therefor, and said first and second leaf members are joined by a
second flexible hinge coupling portion such that relative pivot of
said first and second leaf members produces said advancement and
retraction of said integrally connected drive carriage means.
27. A mechanism according to claim 26, further comprising guide
means for guiding said advancement and retraction of said drive
carriage means along a highly linear displacement path.
28. A unitary, molded transmission linkage structure for use in
sequentially advancing and retracting a lancet needle,
comprising:
a) drive carriage means for carrying, advancing, and retracting the
lancet needle;
b) a hinge structure operatively connected to displace said drive
carriage means and including first and second coupled leaf members
relatively pivotal between a first position thereof in which said
drive carriage means is advanced to project and thrust the lancet
needle into tissue penetration position and a second position in
which said drive carriage means is retracted to withdraw the lancet
needle from the penetration position thereof, wherein said drive
carriage means and said first and second leaf members are
integrally molded in which said drive carriage means is connected
to one of said first and second leaf members by a first flexible
hinge coupling portion, the other of said first and second leaf
members being further coupled to a pivot bearing support therefor,
and said first and second leaf members are joined by a second
flexible hinge coupling portion such that relative pivot of said
first and second leaf members produces said advancement and
retraction of said integrally connected drive carriage means.
29. A unitary, molded transmission linkage structure according to
claim 28, further comprising said lancet needle secured to said
drive carriage means.
30. A unitary, molded transmission linkage structure according to
claim 29, wherein said lancet needle is secured by insertion during
said integral molding of said drive carriage means.
Description
BACKGROUND OF THE INVENTION
This invention relates to lancet devices for use by physicians and
technicians to extract a patient's blood sample, and more
particularly relates to a mechanism for effecting the initial
puncture and thereafter retracting the lancet needle following the
skin puncturing procedure.
In order to reduce trauma to the patient during blood sampling
procedures, automated finger lancet devices have been developed
which eliminate the patient's view of both skin puncture and the
lancet needle or blade itself. As described for example in U.S.
Pat. No. 4,892,097, the lancet needle can be housed within a small
device which provides a spring-driven mechanism for thrusting and
retracting the needle. While such devices obstruct the patient's
view, considerable patient discomfort has been experienced when all
lateral motion of the lancet needle is not prevented. This
disadvantage is eliminated by the lancet actuator in accordance
with the present invention which provides improved patient comfort
in that initial puncture and withdrawal of the lancet needle is
effected in a continuous, smooth motion, and this is done rapidly,
so that little or no lateral movement can take place.
SUMMARY OF THE INVENTION
In accordance with the present invention, an actuator mechanism for
sequentially advancing and retracting a lancet needle includes a
drive carriage for advancing and retracting the lancet needle and a
hinge structure operatively connected to displace the drive
carriage. The hinge structure includes first and second coupled
leaf members relatively pivotal between a first position thereof in
which the drive carriage is advanced to project and thrust the
lancet needle into a tissue penetration position, and the second
pivotal position of the leaf members in which the drive carriage is
retracted to withdraw the lancet needle from the penetration
position. The leaf members can also be pivotal to a third position
in which the drive carriage is retracted prior to initiating the
advancement so that the first position of the leaf members is
pivotally intermediate between the second and third relative
positions thereof. The drive carriage is thus advanced and
thereafter retracted for thrusting and then withdrawing the lancet
needle in continuous reversal motions thereof. The drive carriage
is guided so that the advancement and retraction motions are long a
highly accurate linear path.
In a preferred embodiment, the drive carriage is integrally molded
with a double hinge structure to form a transmission linkage
including two "living hinge" portions which convert the radial
motion of the leaf members into the linear motions of the drive
carriage and lancet needle. The smoothly guided and highly accurate
linear motions of the lancet needle reduce the user discomfort. The
drive carriage accepts removable lancet needle units so that the
actuator is reusable with successive lancet needles. The actuator
includes trigger and rearming structures which tension and release
a torsion spring bearing against one of the leaf members to drive
the transmission linkage and actuator operation.
A second preferred embodiment of the actuator is designed for
single-use disposability, in which the lancet needle is insert
molded within the drive carriage, and accordingly reuse of the unit
by rearming or resetting of the structure is precluded.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a first embodiment of a lancet
actuator device in accordance with the present invention;
FIGS. 2-4 are sectional views similar to FIG. 1 illustrating
sequential operating positions of the actuator mechanism of the
device;
FIG. 5 is a fragmentary sectional view similar to FIGS. 1-4 and
illustrating removal of a lancet unit from the device;
FIG. 6 is a sectional view along a plane indicated at line 6--6 in
FIG. 2;
FIG. 7 is a sectional view along a plane indicated at line 7--7 in
FIG. 2; and
FIGS. 8-10 are cross-sectional views of sequential operating
positions of an actuator mechanism within a second embodiment of
the lancet actuator device in accordance with the present
invention.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Referring to FIG. 1, an embodiment of a lancet actuator in
accordance with the present invention is generally designated by
reference character 10. The actuator 10 accommodates the use of
conventional, disposable lancet needle-and-support-body units A.
The units A comprise a metal needle 11 carried by a plastic body
15. A lancet unit A is inserted into a lancet holder or carriage
means 12 within the actuator 10, as more fully described
hereinafter, prior to operation of the actuator 10 to puncture
tissue in a blood sample extraction procedure, after which the
lancet unit A is removed from the holder or carriage 12 for
disposal. In the actuator 10 of the first embodiment, a split
housing 14 has an access and operation aperture 16 formed at one
end, through which the disposable lancet unit A is inserted and
removed. The actuator 10 also has a cap 18 which is snap-fitted to
the housing 14 to cover the aperture 16 and the inserted lancet
unit A during the blood extraction procedure, and therefore the cap
18 will be exposed to the blood sample and will consequently be
disposable with the used lancet unit A. The cap 18 includes an
opening 18a through which the needle 11 of lancet A can project.
The extension of the cap 18 determines the length of the projection
of the needle portion 11 therefrom, and therefore also determines
the puncture depth when the cap 18 is seated on the donor's skin.
FIG. 1 illustrates the mechanism of the actuator 10 preparatory to
insertion of the lancet unit A and before the actuating mechanism
has been cocked to prepare the actuator for operation. As can be
appreciated, this condition of the actuator 10 also corresponds to
that as would occur after completion of a prior procedure. Thus,
the lancet unit A is positioned within the carriage or holder 12
and the cap 18 is snapped into place. The actuator is then cocked
to arrive at the position shown in FIG. 2, as explained more fully
hereinafter, and is thus ready for operation.
In operation of the actuator 10, the lancet holder 12 carries the
lancet unit A from the retracted position shown in FIG. 2 to the
linearly advanced position shown in FIG. 3 in which the lancet
needle 11 projects from the clearance hole 18a to puncture the
tissue, and then immediately retracts the lancet unit A into the
position shown in FIG. 4. FIGS. 1 and 4 illustrate the same
retracted position of the holder 12, although FIG. 1 also shows the
cap 18 and lancet unit A prior to assembly.
The holder or carriage 12 is integrally molded and connected with a
double hinge linkage structure 13 including first and second hinge
leaf members 20 and 22 respectively, which form a transmission
linkage to convert the radial motion of the leaf members 20 and 22
into linear motion of the holder or carriage 12 and the associated
lancet unit A. The second leaf 22 is directly coupled to the rear
wall of the carriage 12 by a first integrally attenuated, flexible
pivot portion 24 forming a "living hinge" at the forward end of the
second leaf member 22. A second integrally attenuated flexible
portion 26 forms a "living hinge" joining the rear end of the
second leaf 22 to the forward end of the first leaf 20 enabling
relative pivot of the two leaves 20 and 22. A rotatable hub 28 is
integrally molded at the rear end of the first leaf member 20. The
first leaf 20 pivots with the rotation of the hub 28, as indicated
by arrow 29, FIG. 3, which hub 28 is journaled on a stationary
pivot bearing pin 30 which projects inwardly from the housing half
14. The hub 30 has a radially projecting boss 32 which seats the
movable end 34 of a torsion spring 36 which is wound around the hub
30 and drives the hub rotation in the lancet displacement
operation. The generally anchored end 38 of the torsion spring 36
is seated against a spring seat portion 40 of a pivoted trigger
member, generally designated by reference character 42. The trigger
member 42 has an integral pivot bearing pin 44 which is pivotally
supported on an arcuate journal bearing 46 which projects inwardly
from the housing half 14. The interior end of the trigger 42 is
formed as a latch portion 48 which releasably engages a retainer
cam 50 projecting from the hub 28 as shown in FIG. 2. The
releasable trigger latching of the cam 50 retains the tension in
the torsion spring 36 which maintains force against both the boss
32 and the trigger seat 40 in the cocked or armed condition of the
actuator 10 shown in FIG. 2.
In order to arm the actuator 10 from the released condition of the
spring 36 or previously fired position as shown in FIG. 1 in which
the latch 48 is disengaged from the cam 50, a displaceable cocking
member 52 is slidably mounted as shown for rearward movement into
engagement with a laterally projecting foot portion 54 formed on
the end of the boss 32. The cocking, counter-rotation of the foot
54 and hub 28 continue until the cam 50 reaches the latch 48, which
is under tension from the spring 36. The element or cam 50 will
pivot the latch position 48 of trigger 42 upwardly, until said
latch portion engages over the cam 50, to attain the armed or
cocked position as shown in FIG. 2.
The rearward cocking motion of the cocking member 52 also
compresses an attached, biasing coil spring 58 within a blind guide
bore 60 formed in the housing 14. When this cocking motion is
completed, manual disengagement from the cocking member 52 will
permit the biasing spring 58 to return the cocking member 52 to a
neutral position (FIGS. 1, 3 and 4) in which the biasing spring 58
is in expanded condition. Comparison of FIGS. 1 and 2 illustrates
that the counterclockwise cocking motion of the hub 28 pivots the
first leaf member 20 and the second hinge portion 26 downwardly as
indicated by the motion arrows in FIG. 2.
At the other end of the integral linkage structure 13, as best
shown in FIG. 6, the holder or carriage 12 has a laterally
projecting and longitudinally extending guide flange 62 and an
upwardly projecting and similarly longitudinally extended guide
flange 64 which has a modified dove-tail or similarly convoluted
cross-sectional configuration; the two guide flanges 62 and 64 are
slidably displaceable through corresponding, mating receiving slots
formed in the housing halves 14 and 15. FIG. 7 also illustrates
that the slot 68 is vertically split between the housing halves 14
and 15. The guide flanges 62 and 64 insure that the holder 12 and
lancet unit A are displaceable only in a smooth and accurately
linear longitudinal path during advancement and retraction, without
any lateral motion so that the lancet needle 11 enters and
withdraws from the skin at a highly focused point of penetration,
which eliminates any side-to-side motion of the lancet needle and
the resulting penetration trauma and user discomfort experienced
with prior actuator devices.
Since the holder or carriage 12 is constrained to an accurately
linear longitudinal path of the advancement and retraction, the
first hinge portion 24 adjacent the rear wall of the holder 12 is
similarly limited to the highly linear motion of the holder
displacement; therefor the downwardly pivotal motion of the second
hinge portion 26 about the pin 30 pulls the rear end of the leaf 22
downwardly to induce a combined pivot and rearward translation of
the leaf 22 which also pulls the rearward retraction of the holder
12 and lancet unit A through the highly linear path constrained by
the guide flanges 62 and 64. FIG. 2 illustrates the pivotal
position of the leaf members 20 and 22 which retracts the holder 12
into its "armed position" prepared for advancement, in which the
hinge portion 24 is a distance D from the surface of the rotatable
hub 28, which is determined in general by the lengths B and C of
the respective leaf members 20 and 22 and the angle of relative
pivot therebetween.
Referring again to FIG. 3, when the surface of the cap 18 is placed
against the donor's arm, and the trigger surface 56 is manually
depressed the latch 48 is disengaged from the cam 50 and the hub 28
rotates in a clockwise direction, as indicated by arrow 29, under
the influence of spring 36 to begin the lancet needle and skin
puncture procedure. As hub 28 rotates, the leaf member 20 is
pivotally driven upwardly and clockwise as indicated by the
direction of the arrow P. Correspondingly, the leaf 22 will pivot
in a counterclockwise direction from the position shown in FIG. 2
to the intermediate position of FIG. 3. The resulting pivotal
movement of the coupled leaf member 22 produces the linear
advancement of the holder or carriage 12 and lancet needle 11 which
reaches its maximum projection from the cap aperture 18a
(corresponding to the maximum skin puncture depth) when the leaf
members 20 and 22 are linearly aligned, as shown in FIG. 3,
corresponding to the position of hinge portion 24 at maximum
distance E from the surface of the hub 28. Thus, the advancing
displacement of the holder 12 and lancet needle 11 can be expressed
by the difference between the distance E and the distance D. In
addition, however, the torsion spring 36 continues to drive the hub
28, which produces continued upward, clockwise pivotal movement of
the leaf member 20 so that the resulting pivot of the leaf member
22, in which hinge portion 26 becomes elevated relative to the
hinge portion 24, produces a smooth reversal in the advancement of
the holder or carriage 12 and lancet needle 11 and their linear
withdrawal to the maximum position of retraction shown in FIG. 4
which is indicated by the position of the hinge portion 24 at
minimum distance F from the surface of the hub 28. This reverse
stroke of the holder and lancet needle can be expressed by the
difference between the distance E and the distance F.
The operation of the actuator 10 from the armed position in FIG. 2
through the intermediate, skin puncturing position in FIG. 3 and
continuously to the needle withdrawal, retracted position in FIG. 4
can thus be measured by the displacements of the hinge portion 24
from the initially retracted distance D to the maximally advanced
distance E and then retracted to the distance F in the smooth and
highly linear displacement reversals as the leaf member 20 is
pivotally driven clockwise by the tensioned torsion spring 36.
When the actuator operation and lancet puncture procedure are
completed as reflected in the actuator position shown in FIG. 4,
the used lancet unit A is ejected from the holder 12 by sliding the
cocking member 52 forward from its neutral position as shown in
FIG. 4 into the forward position shown in FIG. 5; in this position
the ejector portion 70, on the upper part of the cocking member 52
enters and passes through the slot 72 formed through the rear end
of the holder so that the ejector portion 70 engages and displaces
the lancet unit A from the aperture 16 of the holder 12. The
cocking member 52 is then manually retracted to the neutral
position shown in FIG. 4 so that the ejector portion 70 is
withdrawn from the slot 72. A new lancet unit A can then be
inserted into the holder 12 which is maintained in the fully
retracted position of FIG. 4 during the friction-fit insertion of
the lancet unit A by a stop member 74, depending from the housing
14. The stop member 74 engages the rear end of the guide flange 64
to arrest further retraction of the holder 12. After installing the
new lancet unit A, the actuator 10 can then be armed to the
position shown in FIG. 2 in the cocking operation described
hereinabove with reference thereto.
Referring now to FIGS. 8, 9 and 10, a second embodiment of the
actuator in accordance with this invention is generally designated
by reference character 100. The entire actuator 100 can be employed
for single-use disposability, and therefore the double hinged
linkage structure generally designated by reference character 102
is similar to the double hinge linkage structure 13 in the first
embodiment of the actuator 10, with the exception that a lancet
needle 104 is insert molded within the integrally molded holder or
carriage 106.
In operation, the lancet needle 104 is driven forwardly from the
retracted position shown in FIG. 8 to project from the operation
aperture 108 at the forward end of the split housing 110 as shown
in FIG. 9; the continued pivot of the first and second leaf members
112 and 114 of the linkage structure 102 produces the immediately
sequential retraction of the lancet needle 104 and holder 106 to
the safely withdrawn position shown in FIG. 10. The operation of
the actuator is driven by a flat or leaf spring 116 which is
anchored at one end 118 within the housing 110 and is initially
flexed as shown in FIG. 8 by engagement of the opposite end 120
against a spring seat 122 formed at the rear end of a manual
trigger member 124. The trigger member 124 is maintained in the
armed condition of the actuator 100 and spring 116 by wedged
engagement with a safety tab 126 which is integrally secured to the
housing 110 by a small detachable web 128.
When the actuator 100 is employed to puncture the intended tissue,
the web 128 is fractured to detach the safety tab 126. After
removal of the safety tab 126, the trigger member 124 can be
manually depressed in a downward direction as shown in FIG. 9, thus
pivoting the trigger member about the pivot bearing 130 so that the
spring end 120 becomes unseated from the trigger spring seat 122
and a retaining pin 132 on the trigger becomes unseated from a
retaining notch 134 formed in a retaining cam 136 extending from
the first leaf member 112. The released spring end 120 unflexes
leftwardly, as shown in FIG. 9, so that it engages against a
bearing cam 138 formed on the first leaf member 112 so that the
entire leaf member 112 is driven to pivot in a clockwise direction
about the integrally formed pivot bearing 140 which is journaled in
the housing 110. Resulting relative pivotal motion of the hinge
members 112 and 114 brings the hinge members to the intermediate
position of full extension as shown in FIG. 9 which advances the
integrally hinged holder or carriage 106 slidably through the
extended guide bore 142 formed in the housing 110. The bore 142
opens into the operating aperture 108 from which the advanced
lancet needle 104 is extended to achieve the tissue puncture.
Thereafter as shown in FIG. 10 the continuous clockwise rotation of
the first leaf member 112 under action of the spring end 120 also
drives the smoothly continuous relative pivot of the second leaf
member 114 which pulls the immediately sequential and highly
accurate linear retraction of the holder 106 through the guide bore
142 as shown in FIG. 10 so that the lancet needle is safely
withdrawn from the aperture 108. Since the second actuator
embodiment 100 has a simplified design for single-use
disposability, a rearming mechanism for repeated use is unnecessary
but could be provided.
In light of the foregoing description of the embodied lancet
actuators, modifications will be evident to those skilled in the
design of such mechanisms and are within the broad scope of the
appended claims and equivalents thereof.
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